DoA estimation in EM lens assisted massive antenna system using subsets based antenna selection and high resolution algorithms

In recent times, massive antenna array technology has captured significant attention among wireless communication researchers. This is a field with strong potential to increase rates of data transfer; mitigate interference and serve a large number of users simultaneously. To contribute further to this emerging technology, this paper presents an approach for the line-of-sight (LoS) based direction of arrival (DoA) estimation using the electromagnetic (EM) lens-focusing antenna concept. The EM lens focuses the received signal energy as a function of the angle of arrival (AoA) to a small subset/area of the antenna array. This is advantageous, as it helps to reduce both hardware implementation (RF chains) and the complexity of signal processing in the large number of antennas system. Furthermore, this focusing capability of the EM lens provides additional interference rejection gain which leads to estimate the DoA of user terminals precisely. Hence, in this work, subsets based antenna selection approach and subspace-based high resolution DoA estimation algorithms have been considered in combination with the EM lens assisted massive antenna system. In simulations where the DoA is estimated with the EM lens, the results are comparable with conventional methods of DoA estimation without an EM lens, despite the significantly reduced overall system complexity

Performance analysis of 180\ub0 HRR coupler used for direction finding with an antenna array

This paper presents the performance analysis of  hybrid rat race coupler, widely used in radio frequency (RF)/wireless communication systems to couple the power in the desired way. The  hybrid ring coupler consists of 4 ports, two for the input signals and two for the output signals, where sum and difference patterns of the applied two signals can be obtained at two output ports and usually called sum and difference ports. In this work, the couplers have been designed and simulated at central frequencies (fo) of 2.4 and 10 GHz using different types of substrates such as RT Duroid 5880 and FR4.  Furthermore, the coupler has been used for direction finding (angle-of-arrival estimation) application, where we combine the designed  hybrid rat race coupler with a simple two antenna elements array  (at fo=10GHz and RT Duroid =2.2) and fabricate the circuit in order to validate the performance of the coupler by measuring the direction of arrival (DoA) from  and  ports. The obtained results show that good performance can be achieved with the designs considered in this paper.

A new perspective on the anomalies in the monthly closings of the Dow Jones Industrial Average

Version of RecordThis study explores three types of month effects in the Dow Jones Industrial Average: (a) for a given period, if the mean of monthly percentage changes of each month was different from zero, (b) for a given period, if the mean of monthly percentage changes for a month was different from the means of all the other months, and (c) for a given period, if the variance of the monthly percentage changes for a month was different from the variances of all the other months. For our entire data set (May 1896 to December 2002) we find that the means of monthly percentage changes of only July, August, January and December were significantly greater than zero (months put in descending order). But the means of none of these three months were significantly higher compared to the means of all the other months. With a mean percentage change of -1.25%, only September appears with significant negative returns. And this mean is significantly lower compared to the means of all the other months. In other words, for the entire data set, we have a negative September effect. Month effect with respect to variance (variance of monthly percentage changes for a month being significantly different from all the other months) was found for January, February and December (lower variances), and April (higher variance). When we look at the first half of the twentieth century versus the second half, we see more pronounced month effects in the second half - considering all three types of effects we analyze. December exhibited all three types of effects in this period. When we sub-divide the last century into four 25-year periods, we find more pronounced month effects in the last quarter than in the previous three quarters. When we sub-divide the data into 10-year periods, we do not find any consistent and discernible pattern. The month effect varies with the time period we consider and the type of effect we analyze. Though one would expect the DJIA stocks to be free from seasonal patterns since each one of them are closely followed by a large number of analysts, the existence of any type of month effect is surprising. However, given that no discernible pattern is detectable is a reflection of efficiency of the DJIA stocks to a large degree.Hamid, S. A. & Dhakar, T. S. (2003). A new perspective on the anomalies in the monthly closings of the Dow Jones Industrial Average (Working Paper No. 2003-04). Southern New Hampshire University, Center for Financial Studies

A Modified Algorithm of Improved Explicit Euler’s Method To Solve Initial Value Problems.

Details can be found in the PDF of the article

ARM Based Security & Safety System for Base Transceiver Station

The main aim of this system is for Maintenance, Safety & Security of Base Transceiver Station (BTS) site and the tower . The major problems faced include the theft of Wires & Diesel , the fluctuation of Temperatures, unauthorized person entry, unnoticedfuel amount ,Current taken by load and the technician’s time management. The instant message about the each activity happening in the site given byGSM modem. The temperature sensors will sense the temperature of the room and if it rises above the threshold value the GSM module will send the message to the mobile. Thetemperature values are displayed on LCD, the controller gives command to cooling Fan to ON & Real time Images recording on PC by using MATLAB software with GUI .The cell site Base Transceiver Station (BTS) which are operated by Diesel generator .When the fuel level goes below the set value a message is sent to the technician requesting for refilling & with Real time Images recording with on PC by using MATLAB software. Door open/close sensor is used for indication of door opening and closing. Wire Theft Status indicated by IR Sensor .The site door can be accessed only through the RFID system. The situation in the site is updated to the technician through messages. PIR sensor used to detects the presence of humans inside the room. The system includes a Current sensor to measure Load Current & Humidity Sensor to sense humidity of BTS room with Real time Images recording on PC. Camera record BTS room. The value of Temperature & Humidity of BTS room, Diesel Level of Generator& Load Current are Logged in PC with respective time & date. Our project improves the performance ability of BTS. This technique is remote controlling and monitoring can be implemented at each and every BTS tower to look after the safety and management of its network

Bianchijev kozmološki model tipa I u samotvornoj kozmologiji

A five-dimensional Bianchi type-I space-time is considered in the presence of a perfect fluid source in Barber\u27s (Gen. Relat. Gravit. 14, 117, 1982) second self-creation theory of gravitation. The model is presented using a relation between the metric potentials and an equation of state. Some physical and kinematical properties of the model are discussed.Razmatramo Bianchijev prostor-vrijeme tipa I u pet dimenzija, uz prisustvo perfektne tekućine, u drugoj Barberovoj samotvornoj teoriji gravitacije (Gen. Relat. Gravit. 14, 117, 1982). U modelu pretpostavljamo relaciju među metričkim potencijalima i jednadžbu stanja. Raspravljamo neke fizičke i kinematičke odlike modela

Review of Leaf Unhealthy Region Detection Using Image Processing Techniques

Abstract- In agricultural  field the plants comes to an attack from the various pets bacterial and micro-organism diseases. This diseases  attacks on the plant leaves, steams, and fruit part. This present review paper discussed the image processing techniques which is used in performing the early detection of plant diseases through leaf feature inspection. the basic objective of this work is to develop image analysis and classification techniques for extraction and finally classified the diseases present on leaf. Image of leaf is captured  and the process is performed and to determine the status of each plant. Here proposed model  divide into four parts. The  image preprocessing including normalization and contrast adjustment; segment the region of interest  determine by using color transform YCbCr and bi-level thresholding for statistical usage to determine the defect and severity area of plant leaves. The texture feature extraction using statistical GLCM (Gray Level Co-occurrences Matrix)  and color feature by means values.[1] Finally classification achieved using random markov model

Bianchijev kozmološki model tipa I u samotvornoj kozmologiji

A five-dimensional Bianchi type-I space-time is considered in the presence of a perfect fluid source in Barber\u27s (Gen. Relat. Gravit. 14, 117, 1982) second self-creation theory of gravitation. The model is presented using a relation between the metric potentials and an equation of state. Some physical and kinematical properties of the model are discussed.Razmatramo Bianchijev prostor-vrijeme tipa I u pet dimenzija, uz prisustvo perfektne tekućine, u drugoj Barberovoj samotvornoj teoriji gravitacije (Gen. Relat. Gravit. 14, 117, 1982). U modelu pretpostavljamo relaciju među metričkim potencijalima i jednadžbu stanja. Raspravljamo neke fizičke i kinematičke odlike modela